Systems and Methods for Enhancing Teleconferencing Collaboration

ABSTRACT

An advanced video teleconferencing system facilitates an engaging and realistic video conferencing experience. Key design elements and video, audio, and control capabilities are provided for a video conferencing experience that cannot be attained with conventional methods, which elements and capabilities include careful design of the table and room at each site, supplementary displays showing imagery in a mirrored manner, networked environmental control, an AutoDirector with keyword and gesture recognition, and audio reflection from a display or beam splitter.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. Ser. No. 12/036,134 filed Feb.22, 2008 (Attorney Docket No. APPL0078) which claims priority to U.S.Provisional Patent Application Ser. No. 60/891,478, filed Feb. 23, 2007and is a continuation-in-part of U.S. patent application Ser. No.11/461,373, filed Jul. 31, 2006, which is a continuation of U.S. patentapplication Ser. No. 10/911,079, filed Aug. 3, 2004, now U.S. Pat. No.7,092,002, the entirety of each of which is incorporated herein byreference hereto.

BACKGROUND

1. Technical Field

The invention relates to teleconferencing. More particularly, theinvention relates to methods for better facilitating collaboration invideo teleconferences.

2. Description of the Prior Art

Current video teleconferencing systems are deficient in their ability tosupport effective collaboration among conference participants,engendering a feeling of remoteness amongst the participants that iscontrary to the intended benefits of the system. This deficiency can beattributed to a number of shortcomings that collectively diminish theeffectiveness of the communication.

Specifically, current systems do not:

-   -   Provide spatial and visual cues that create within the        participants a sense of being assembled at a single location    -   Enhance the same-room feeling by directing the view of        participants towards supplementary displays such that        participants at all sites feel they are looking at a common        position in space;    -   Use networked control of the conferencing environments so that        lighting and other visual factors appear similar among sites;    -   Offer adequate software tools for maintaining the        synchronization of the conference environments;    -   React to cues provided within speech patterns and content; and    -   Provide accurate audio cueing, i.e. remote participant voices        often emanate from a location other than where the image of the        remote participant is displayed.

It would be advantageous to provide an advanced video teleconferencingsystem that facilitates an engaging and realistic video conferencingexperience.

SUMMARY

The invention is an advanced video teleconferencing system thatfacilitates an engaging and realistic video conferencing experience. Theinvention provides key design elements and video, audio, and controlcapabilities for a video conferencing experience that cannot be attainedwith today's conventional methods. These include careful design of thetable and room at each site, supplementary displays showing imagery in amirrored manner, networked environmental control, an AutoDirector withkeyword and gesture recognition, and audio reflection from a display orbeam splitter.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a video teleconferencing site according to the preferredembodiment of the invention.

FIG. 2 shows an overhead view of a teleconferencing site according tothe preferred embodiment of the invention.

FIG. 3 shows a video teleconferencing site incorporating supplementarydisplays according to the preferred embodiment of the invention.

FIG. 4 shows a schematic of the routing of signals to supplementarydisplays according to the preferred embodiment of the invention.

FIG. 5 depicts the reflection of audio from the main display towards theparticipants according to the invention.

FIG. 6 shows a one-person video teleconferencing station according tothe preferred embodiment of the invention.

FIG. 7 shows a one-person video teleconferencing station with audioreflected from a beam splitter according to the preferred embodiment ofthe invention.

DESCRIPTION Table and Room Geometry

FIG. 1 shows a video teleconferencing site according to the preferredembodiment of the invention. Each participant at the videoteleconference site 100 is seated at a station 150 around the perimeterof the table. A number of video cameras 500 capture images of the localparticipants in a variety of views (e.g. close up, wide angle) forpossible transmission to remote conferencing sites.

The table 120 at each site is positioned and/or shaped such that when animage of a remote site is displayed on the main display 200 at the localsite, the image of the table at the remote site appears as acontinuation of the table at the local site. The seamless alignmentbetween the physical table at the local site and the displayed table atthe remote site reinforces the sense that the local and remoteparticipants are together in a single room. In the preferred embodiment,the table forms a substantially semicircular shape, with the maindisplay 200 aligned with the straight edge of the table. When anothersite with a similarly shaped table 175 is shown on the display, the arcof the local table appears to be reflected at the other site, providingthe illusion of a single, circular table.

Each station is also fitted with a collaboration interface 300. In thepreferred embodiment of the invention, the interface consists of apen-enabled touch screen display 350 with which the participant can viewand annotate conference materials (e.g. slide presentations), exchangenon-verbal information (e.g. messages) with other participants, accessshared applications (e.g. a collaborative whiteboard), and accessnetworked based information (e.g. the World Wide Web). The collaborationinterface is preferably positioned to one side of the station so as notto block the view of the participant. Placement of the interfacedirectly to the side of each participant also narrows the spaceavailable to the participant, providing an intuitive cue to theparticipant that he should remain seated within the field of view of thevideo camera or cameras providing coverage of the participant.

FIG. 2 shows an overhead view of a teleconferencing site according tothe preferred embodiment of the invention. As can be seen in the figure,a wall 130 is positioned a short distance behind the participants seatednear the apex 125 of the semicircular table. For purposes of thediscussion herein, a short distance is short enough that otherindividuals do not feel comfortable lingering behind the seatedparticipants, e.g. the distance is within an individual's personalspace. Best current estimates for personal physical space are about 24.5inches (60 centimeters) on either side, 27.5 inches (70 centimeters) infront and 15.75 inches (40 centimeters) behind for an average westerner.(http://en.wikipedia.org/wiki/Personal_space) The relatively smallclearance between the seated participants and the wall behind theparticipants ensures that any other individuals in the room will notlinger behind the seated participants and therefore will remain out ofthe field of view of the video cameras intended to show only the seatedparticipants. This alleviates the confusion of the remote participantsthat would result were individuals other than the seated participants tobe periodically entering and leaving the field of view of various videocameras.

Supplementary Displays with Mirrored Imagery

FIG. 3 shows a video teleconferencing site incorporating supplementarydisplays according to the preferred embodiment of the invention. Whilethe main display preferably shows images of participants at remotesites, the supplementary displays 250 are used to show otherinformation, such as maps, slides, text, or video. At each site, thesupplementary displays are mounted such that all participants may viewthem, preferably above the main display. In the preferred embodiment,the supplementary displays are mounted sufficiently offset that when alocal participant is viewing a supplementary display, it is clear toremote participants viewing images of the local participant the he isnot intending to make eye contact. For purposes of the discussionherein, the size/offset of the supplementary displays are such that whenviewed by the local participant, the angular offset between the localparticipant's eyes and the line of eye-contact with the remoteparticipant is readily perceptible to the remote participant. That is,when the local participant views the supplementary displays, it isreadily apparent to the remote participant that the local participant isnot making eye contact and is looking somewhere else.

To better quantify, consider: GAZE-2: Conveying Eye Contact in GroupVideo Conferencing Using Eye-Controlled Camera Direction, RoelVertegaal, Ivo Weevers, Changuk Sohn and Chris Cheung, CHI '03:Proceedings of the SIGCHI conference on Human factors in computingsystems, pages 521-528, 2003, who in turn cite Chen, M. Leveraging theAsymmetric Sensitivity of Eye Contact for Videoconference. InProceedings of CHI 2002. Minneapolis: ACM Press, 2002. This recountsuggests that to avoid the appearance of eye gaze being lowered orotherwise skewed, the video camera needs to be located to within 1degree horizontally and 5 degrees vertically from the on-screenrepresentation of the eyes of each conversational partner. An intuitivecue is thus provided to the remote participants that their attentionshould be directed somewhere other than to the eyes of the localparticipant.

If more than one supplementary display is used, the displays arepreferably mounted side by side, as shown in the figure. To betterfacilitate collaborative discussion, the supplementary displays willtypically display the same information at all sites so equipped.However, if the displays at a local and a remote site display the samecontent on supplementary displays at the same position relative to theparticipant, the same-room experience is diminished. For example,consider a local and a remote site each with two supplementary displaysmounted in a side-by-side configuration above the main display, as shownin FIG. 3. Suppose that the left display 251 at each site shows a mapand the right display 252 at each site shows a photograph. Suppose that,based on the current conversation, both the local and remoteparticipants focus their attention on the map. Participants at the localsite looking up-and-left to view the map will see remote participantsdisplayed as if they are looking up-and-right at the photo. Conversely,it will appear to the remote participants that the local participantsare looking up-and-right at the photo while they are actually lookingup-and-left at the map. Neither the local or remote participants areprovided a sense that they and their counterparts are looking at acommon point in space.

To address this deficiency, the information routed to the left displayat one site is routed to the right display at a second site. Thisoperation is illustrated schematically in FIG. 4. More generally, thecontent shown on a display at a first site is shown on a correspondingdisplay at the second site positioned in a symmetric position relativeto a centerline 255 of the conference site. The invention may thus beextended to more than two supplementary displays. Mirroring the contentof the displays in this manner restores the local and remoteparticipants' sense that they are viewing supplementary display contentat a common point in space, greatly reinforcing the same-roomexperience.

Synchronization of Conferencing Environments

To further strengthen the same-room experience of the conferenceparticipants, the invention provides a mechanism for synchronizing theenvironments of the various conference sites.

For example, when a participant at a first site adjusts the lightingcontrols at the first site, the lighting levels are adjusted at both thefirst site and at any synchronized sites. This concept may be extendedto the audio levels, climate control, and security levels of theconference sites. For example, if an RFID badge worn by a participantentering one site indicates that he does not possess clearance to viewmaterial currently displayed on the supplementary displays orcollaboration interface, the supplementary displays or collaborativeinterfaces may be blanked at all sites.

The invention ensures synchronization via a database that stores theconference state. The state of the conference is stored in ahierarchical, tree-like data structure. The root node of the treecorresponds to the entire conference state. Primary branches of the treemay represent lighting, audio, climate, and security. Smallersub-branches of the tree may correspond to individual banks of lights.Other primary branches of the tree track which participant stations areoccupied and the state of the various collaboration tools (e.g.collaborative whiteboard contents and senders, recipients, and contentof private messages).

Each site maintains a local copy of the entire conference state, and, atany time, one site is designated as a conference master. Conferencesites that wish to have a portion of the conference state synchronizednotify the conference master by subscribing as a listener to aparticular node within the tree. If a subscribing site detects a changein the conference state (e.g. a participant at the site has adjusted aphysical control associated with audio levels) within the portion of thetree radiating from the subscribed node (e.g. the audio levels branch),it informs the conference master of the change in state. The conferencemaster then notifies all sites that have subscribed to the portion ofthe tree affected by the change in state. The notification contains theupdated values of the conference state in the affected region of thetree. Each notified site then updates its local copy of the conferencestate accordingly.

Thus, the invention stores the conference state in a distributed fashionand maintains synchronization of the conference state in an event drivenmanner. The redundant storage of the conference state ensures that,should the conference master become unavailable due to a failure (e.g.network outage), a new conference master can be selected.

The database, can, however, be polled for all or a portion of theconference state. This functionality allows sites to join a conferencealready in progress. Upon joining a conference and subscribing to one ormore nodes within the tree, the joining site can poll the database forthe subscribed portion of the tree and synchronize its state to thestate shared by the conference sites already present.

Finally, each site may additionally store a local state for sitedependent information. Such information may include, for example, thelighting levels for lights with no functional equivalent at other sites.While other sites may store similar information, the invention does notprovide for subscription and updating of the site dependent information.

Lispy Programming Language

In the preferred embodiment of the invention, the database storingconference state is implemented using Lispy—a novel programminglanguage. Lispy is ideally suited for the synchronized hardware controlrequired by the invention.

Features and Background

One feature of Lispy is the ability to link multiple interpreterstogether over a network and have network transparency of stack symbollookups. It is essentially a network transparent programming language.This makes Lispy ideal for network-centric applications, such as videoconference collaboration systems.

Lispy's other features involve its name/value/next node primitive. Apartfrom the name field (value/next are equivalent to car/cdr), Lispy islargely similar to Lisp or Scheme in structure, and we attempt to useScheme function names where applicable.

Lispy has a native Java API, allowing manipulation of Lispy structuresin a native Java environment.

Lispy also provides an event notification system that can notifyentities of changes to Lispy structures, such as the setting of a valuefield. Entities can subscribe as listeners to a node, and receivenotification of changes made to the node.

This notification system is also used as a communications layer,allowing messages to be passed and broadcast to interested partiesanywhere on the network, simply by setting the value field of a knownnode to the content of the message. This is the basis of allcommunication within the synchronization system described above.

Earlier, simplified versions of Lispy maintain a network transparenttree configuration and provide message-passing system with a Javainterface. The implementation of a dereference function and a few simpleextensions, however, have rendered more recent versions of Lispy a trueprogramming language with full Turing Equivalence.

Primitives

Lispy is an extension, and thus can use as a value any Java Object.However, for linguistic purposes, there are only three fundamental typesthat Lispy can handle in external (printable/parsable) format—strings,symbols, and numbers.

A string is enclosed in quotes:

“hello world”

A symbol is just a string of letters and digits, underscore, and hyphen,with no spaces:

mysymbol

A number is a string of digits, optionally a decimal expression:

386, 3.14159, 0.34567

Internally, any parsed number is considered a double.

The null symbol has special handling in Lispy. It represents a nullvalue or null pointer.

A symbol-path is a series of symbols separated by periods (“.”)specifying a path into a tree structure:

“entry.address.city”

Lists

Lists of objects can be created by enclosing them in square brackets:

[“apple” 3.14 x]

Nodes

The fundamental structural type in Lispy is the Node. A Node, analogousto a Lisp cell, has three fields: the name, the value, and the nextpointer.

node: (<name> <value> <next>)

The <value> and <next> fields are analogous to the car and cdr cellfields in Lisp. The <name> field provides a symbolic lookup capabilitywhich is ideal for configuration applications.

A node can be expressed in Lispy using parenthetical syntax. To specifya node with the name “programmer”, the value “braddock”, we can input:

(programmer “braddock”)

Note that the <next> pointer is not specified explicitly. <next> getsset explicitly, for example in a list.

[(programmer1 “braddock”) (programmer2 “Rudy”)]

A list is, in fact, nothing but a series of linked Nodes. Above the listwas written as:

[“apple” 3.14 x]

It is actually implemented inside Lispy as:

[(null “apple”) (null 3.14) (null x)]where the <name> fields are implicitly all null.

The <value> field inside a full node expression may also be a list, suchas

(authors [“Clarke” “Asimov” “Vonnegut”])

In this case, internally the <value> field is a pointer to the firstNode of the list. Also, a special syntax can be used to build trees ofvalue-name pairs.

(braddock  (phone “617-230-9108”)  (address   (street “3100 St. PaulSt.”)   (city “Baltimore”)   (state “Md)  ) )

Functions

A function can be called by naming the function as the first value in alist. For example:

[print “hello world”]

Functions can take multiple parameters, such as

[wait-for-change my.semaphore “1”]

Multiple functions can be placed in a list for sequential execution:

[  [print “hello world”  [set! x 386]  [print “The value of x is:”] [print x] ]

Lambda

An essential yet infrequently used function is Lambda. It pushes ascoped variable onto the stack and then executes another function withit.

[lambda (x “hello”) [x “world”]]

Inclusion of Lambda guarantees Turing Equivalence, and can be the basisfor many other functions.

Context (the Stack)

The symbol stack is called the Context of execution, since it is not asimple flat stack. All symbols that are specified for interpretationmust have a corresponding entry in the Context, including corefunctions. The current context can be viewed using the “get-context”function. For example:

[write [get-context]]which will print the symbol table. Note that all data in the table willbe printed, which could be enormous.

The Context need not be viewed as anything special. It is just a list ofname/value Nodes like any other structure in Lispy. In fact, in manyways Lispy was designed to be one big tree-structured symbol stack.

Existing symbols may be modified or added to the stack with the set!function:

[set!×“hello world”]

One of the more interesting features of Lispy over other lambdalanguages like Lisp or Scheme is its symbol-path capability. Since everylist of nodes may have it's name fields referenced as a stack, there isa more structured context that a traditional flat stack. For example:

[set! last-names  [   (braddock “Gaskill”)   (brian “O'Reilly”)   (rudy“yukich”)  ] ]sets the symbol “last-names” to the specified list. The entire list canbe treated as first-class structured symbols. For example:[print last-names.brian]

The list itself can also be treated as an object, of course. Forexample:

[print last-names]will print the entire contents of the last names list.

Formal Syntax

This is the approximate formal syntax of Lispy in Augmented BNF:

WS = SPACE/HTAB/CR/NL number = (1*DIGIT*1“.”*DIGIT)/(“.”1*DIGIT)char-val = DQUOTE*(%x20-21/%x23-7E)DQUOTE symbol =ALPHA*(ALPHA/DIGIT/“-”/“_”) lexical-token =symbol/char-val/number/“(“/”)“/”[“/”]” symbol-path =symbol*(“.”<symbol>) sym-name = symbol-path sym-value =symbol-path/char-val/list/number/implicit-list list = “[” node-expr*(1*WS<node-expr>) “]” implicit-list = full-node-expr*(1*WS<node-expr>)node-expr = full-node-expr/value-node-expr full-node-expr = “(” sym-name1*WS sym-value “)” value-node-expr = sym-value

Autodirector

The invention incorporates an AutoDirector that emulates the behavior ofa highly experienced human video director. The AutoDirectorautomatically selects, from among one or more video camera feeds andother video inputs, a video signal for transmission to remote videoconferencing sites, and, optionally, a video signal for display on oneor more supplementary displays. In this manner, the flow of conversationamong the participants of a local video conferencing site is seamlesslyreconstructed at the remote teleconferencing site for viewing by theremote participants and topical video content is routed to thesupplementary displays. In conferences incorporating more than twosites, the AutoDirector preferably selects which of the several videosignals received from remote sites will be shown on the primary localdisplay.

Keyword Based Video Selection

As noted in the referenced patent application, the AutoDirector reliesprimarily upon audio activity (i.e. the presence or absence of speakingas detected by a particular microphone) to determine which of thevarious available video feeds and video inputs it will select.

However, the AutoDirector may also respond to the content of the audiosignals obtained from a microphone. Specifically, the AutoDirector mayselect a particular video feed or video input upon recognizing one of anumber of predetermined keywords stored in a database. For example, theAutoDirector may select a video feed displaying a participant if theparticipant's name is detected within one or more audio signals. Aparticular video input (e.g. a slide presentation) may be displayed(either on the main or supplementary displays) if a correspondingkeywords (e.g. slide) is detected. The AutoDirector thus responds toverbal cues inherently present within the conversation.

Additionally, predefined, explicit verbal commands may be used. Forexample, a particular participant may request that he be shown by saying“show me”. A conference administrator may verbally override theAutoDirector's automatic behavior by saying “show Bob”. Finally, aparticular video input may be selected with a command such as “showdocument”.

Gesture Based Video Selection

The AutoDirector is also capable of recognizing and reacting to gesturesmade by the participants. Using techniques well known in the prior art,the AutoDirector can compute the look-direction and gaze-direction ofone or more participants and from this information determine a focus ofattention within the room. The focus of attention may then be consideredin selecting an appropriate signal for transmission. For example, if theAutoDirector determines that a specific participant is the focus ofattention within the conferencing site, it may select a video feed thatdisplays the participant. The AutoDirector may also determine the focusof attention by recognizing manual gestures such as pointing. In someinstances, the gesture recognized may suggest that the participantperforming the gestures is himself the focus of attention. For example,the AutoDirector may select for transmission a video feed showing aparticipant pounding the table in frustration or raising his arms infrustration.

Reflected Audio

In conventional video teleconferencing systems, audio from the remotesite is typically produced by speakers separated from the local videodisplay. The audio heard by participants does not appear to emanate fromthe displayed image of the remote participant. While a stereo speakerconfiguration of speakers positioned on opposite sides of the displaydoes provide a stereo image centered on the display, the effect providedis not the same as a single source emanating from the speaker. Theresulting false audio cueing engenders a sense of fatigue among theparticipants.

Audio Reflected from Main Display

To provide accurate audio cueing, the invention incorporates an audiospeaker directed at the main display on which images of the remoteparticipants are displayed. The audio emanating from the speaker isreflected from the display and towards the listening participants. Theconversation rendered by the audio speaker is thus perceived to emanatedirectly from the participant displayed on the monitor.

FIG. 5 depicts the reflection of audio from the main display towards theparticipants according to the invention. The speaker 21 is mountedbeneath the surface of the table under an acoustically transparentmaterial 22 and aimed at the main display 12. Audio is thereby reflectedfrom the main display towards the participants 23, giving the illusionthat the audio is originating from the center of the display.

This effect may be further enhanced by selecting a highly directionalaudio speaker and shielding the speaker in a manner that blocks thestraight line transmission pathways between the speaker and thelistening participants. For example, in the preferred configuration, theaudio speaker is recessed within a table on which the main displayrests. The recess is shaped and the speaker positioned to allow audio toemanate towards the monitor but not towards the listening participants.

Audio Reflected from Beam Splitter

FIG. 6 shows a one-person video teleconferencing station according tothe preferred embodiment of the invention. In such a one-person station,the table-mounted reflected audio configuration described above isunsuitable for two reasons:

-   -   There may be insufficient table space between the local        participant and the display to mount the speaker without risking        obstruction of the speaker by objects on the table, such as        papers and the local participant's arms, and    -   A beam splitter is positioned in front of the display to provide        improved eye contact with the remote participant, and the angle        of the beam splitter will reflect sound away from the local        participant.

FIG. 7 shows a one-person video teleconferencing station with audioreflected from a beam splitter. As mentioned above, a beam splitter 650is positioned within the station 600 and in front of the display 625 atapproximately a forty-five degree angle. A video camera 675 ispositioned above the beam splitter to capture an image of the localparticipant as reflected from the front surface of the beam splitter.The participant views the display through the beam splitter. A darkenedenclosure 680 surrounding the display, camera, and beam splitter ensuresthat the participant's view of the display and the camera's view of theparticipant are not corrupted by ambient light. A speaker 690 is mountedin the same plane as the camera, above the beam splitter. Soundemanating from the speaker is reflected by the beam splitter towards theparticipant, providing the illusion that the audio is originating fromthe center of the display, coincident with imagery of the remoteparticipants.

Although the invention is described herein with reference to thepreferred embodiment, one skilled in the art will readily appreciatethat other applications may be substituted for those set forth hereinwithout departing from the spirit and scope of the present invention.Accordingly, the invention should only be limited by the Claims includedbelow.

1. A video teleconferencing site, comprising: a main display for showingimages of teleconference participants at remote teleconferencing sites;one or more supplementary displays for showing other informationcomprising any of maps, slides, text, or video; means for mounting saidsupplementary displays at an angular offset from said main display forviewing by all participants; wherein said supplementary displays aremounted sufficiently offset from said main display such that when alocal participant is viewing a supplementary display, it is clear toremote participants viewing images of said local participant the localparticipant does not intend to make eye contact with them; wherein saidone or more supplementary displays are mounted to provide an intuitivecue to said remote participants that their attention should be directedsomewhere other than the eyes of said local participant when they areviewing said one or more supplementary displays.
 2. The videoteleconference site of claim 1, wherein if more than one supplementarydisplay is used, the displays are mounted side by side; and whereininformation routed to a supplementary display at a local site is routedto a mirror image supplementary display at a remote site.